In recent years, a polypropylene-based fiber and non-woven fabric have been finding use in various applications such as a disposable diaper, a sanitary product, a hygienic product, a clothing material, a bandage, and a packaging material. A reduction in basis weight of the non-woven fabric is important because weight reductions are typically required for those products. In addition, a non-woven fabric excellent in dispersibility of its fibers and having a small mesh size is needed particularly for the disposable diaper, the sanitary product, or the like because the prevention of the oozing of a hot-melt adhesive or the prevention of the leakage of urine is required for such product.
A method of improving the dispersibility of fibers constituting a non-woven fabric is, for example, to reduce the denier values of the fibers. A method of achieving the reductions in denier values of the fibers is, for example, the production of the non-woven fabric by a meltblown method, and in this case, the denier values can be reduced by, for example, a reduction in discharge amount, an increase in flow rate of compressed air (see Patent Literature 1). However, when the production condition is adopted, the fibers cannot withstand a spinning tension and hence are apt to cause end breakage. In addition, a liquid droplet has fallen onto a web to cause a defective molding called a shot in some cases.